Epstein-Barr virus-encoded latent membrane protein 1 co-expresses with epidermal growth factor receptor in nasopharyngeal carcinoma

Latent membrane protein 1 (LMP-1) is the only Epstein-Barr virus (EBV)-enco ded oncogenic protein that has been detected in nasopharyngeal carcinoma (N PC), a cancer that is closely associated with EBV, Previous in-vitro studie s have demonstrated that LMP-1 can upregulate epidermal growth factor recep tor (EGFR) in epithelial cells. It was not established whether this cellula r effect exists in NPC. To assess the association between LMP-1 and EGFR in NPC tissues, 60 NPC specimens were examined by immunohistochemistry using anti-LMP-l antibody (CS 1-4) and anti-EGFR antibodies (EGFR 1, EGFR 1005), The results revealed that 41 (68.3%) specimens were immunopositive for LMP- 1 and 44 (73.3%) specimens over-expressed EGFR, Morphologically, the expres sions of LMP-1 and EGFR were homogeneously distributed in the tumor nests. In addition, the correlation between LMP-1 and EGFR was statistically signi ficant (P<0.001, chi(2) test, d.f. = 1). To elucidate further the correlati on between LMP-1 and EGFR in vivo and in situ, an indirect dual immunofluor escence assay was conducted, using secondary antibodies conjugated with flu orescein isothiocyanate (FITC) or indocarbocyanine (Cy3), The results discl osed an intimate co-expression of LMP-1 and EGFR, In summary, the data indi cate that over-expression of EGFR is a common phenomenon in NPC, and that E GFR is co-expressed with LMP-1 in NPC, Thus, EBV may play a role in the tum origenesis of NPC through the effects of LIMP-1 and EGFR.